The document summarizes a study on enhancing soybean nodulation and crop yields through inoculation in a soybean-maize rotation in Uganda. Inoculation with compatible rhizobia strains increased soil rhizobia populations over three seasons compared to the control. Inoculation also improved nodulation attributes like nodule number and color. While inoculation did not significantly increase yields, it was found to be economically and environmentally beneficial. The study recommended further research to optimize the benefits of inoculation technology for smallholder farmers in Uganda.

1. 5/27/2010
Rationale
Enhancing SNB populations and
crop yield through inoculation in a • Legume inoculation practice
soybean-maize rotation in Mabira uncommon in Uganda despite
benefits e.g. N
benchmark site, Uganda
• Compatible SNB strains often
p
Uzatunga, I., M.C. Rwakaikara- Silver, J. Zawedde, C. Nkwiine, P. few/absent
Ssenyonga, B. Isabirye and M.J. N. Okwakol
• Yields are low & soils
impoverished
• Resource limited farmers desist
growing soybean despite its
dietary and economic benefits.
Objective Methodology
• Enhance SNB populations, nodulation effectiveness • Researcher & farmer field N P I I+P C
and crop yields through inoculation technology demonstrations/ expts in
Bulyatete, Kyambogo, Soy Soy Soy Soy Soy
Natyole & Nagojje TAL
102
• Initial soil (chem phys
(chem, phys,
MPN) analysis,
• Nodulation attributes (No,
intern coloration, Maize Maize Maize Maize Maize
• strain occupancy (Ab-
agglutination method),
Methodology cont’d
• At maturity grain Yield
(soybean & maize)
• 2nd season plot split x2,
planted to maize and
soybean, practices &
parameters assessed
same as before
• 3rd season similar to first
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Nodulation attributes
Methodology cont’d
• Nodule occupancy • Data subjected to ANOVA if normally
distributed
• Nodule Scores (no. Control
size. Distribution,
coloration, vigour) • LSD( 0 05) t t f mean separation
LSD(≤0.05) test for ti
• Plant vigour
(Farmers score)
Inoculation
Table 1 Initial soil parameters
Site pH %OM %N Av P (mg MPN
kg-1)
Nagojje T. 6.0 2.76 0.16 1.84 17
Results
C
Kyambogo 5.9 1.53 0.10 1.63 6
Natyole 5.8 3.37 0.19 1.95 0
Bulyantete NA NA NA NA 0
CV 5.5 3.00 0.20 15.00
SNB population dynamics over seasons
Nodule score & Nase activity
9000
7811 7758
8000
7000 TRT NOD SCORE Nase activity
Cells per gram of soil
6000 (No., distr, vig) (%) (pink nods)
5000
3954
4502
control 8.1 (M) 71.0
4000
3000 LNB 12.3 (E) 91.8
2000 1704
1000
LNB+P 11.2 (E) 97.5
224 16 48 31
0
Season 1 Season 2 Season 3 N 6.5 (M) 67.7
Seasons
LNB LNB+P Control P 8.0 (M) 84.7
E= excellent, M =medium
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Nodulation attributes cont’d Farmers ranking
• Nodule occupancy ranged from 2.67
50-80% ( LNB, LNB+P)
LNB + P
2.0
3.67
Soybean& maize yields & cash income
Continuity of CSM-BGBD activities
3000000 3000 500,000 1600
420,700
2438000 1400
N e t I n c o m e p e r H a (U g . S h s )
2500000 2500 400,000
M a iz e Y i e ld (K g ) P e r H a
N e t In c o m e P e r H a (U g . S h s .)
1200
S o ya Y ield p e r H a
2000000 2000 271,200
• Farmers linked to a running project
300,000
1000
1500000 1500 200,000 800
1000000 825000 1000 600
Vegetable oil crops & markets
602848 100,000
400
500000 500
-
200
0
Control LNB Fertilizer Chemical Fertilizer
0
-100,000
Control LNB fertilizer Chemical fertilizer
-55,400 0 • Proposal to GEF Small Grants
Soil Fertility Inputs Soil Fertility Inputs
Net Profit Yield
Net Income (ha-1) Yield (kg ha-1)
Conclusions Conclusions cont’d
• Inoculation, P & host enhance SNB popns • Improved nodulation not translate into
c/f inventory results signif yields but may be economically &
environmentally viable
• V i bl competitive ability f i
Variable titi bilit for inoc strain
t i
• Further studies recommended.
• Efficiency (Nase activity) 68-97.5% (LNB +
P& LNB)
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Acknowledgement! END!
• Farmers & other stakeholders
• GEF, UNEP, CIAT-TSBF
• MAK
• COLLABORATORS • THANK YOU FOR YOUR ATTENTION
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